Combinations of herb extracts having synergistic antioxidant effect, and methods relating thereto

ABSTRACT

The present invention comprises mixtures of herb extracts which exert synergistic antioxidant effect and comprise the herb  sophora  and kudzu. Skin care preparations incorporating such herb extract mixtures, and their methods of preparation and use, are also claimed.

FIELD OF THE INVENTION

The present invention relates to combinations of herb extracts whichprovide synergistic antioxidant effects when used in personal careproducts including body washes, lotions, liquid hand soaps, sunscreens,shampoos, and the like. The invention also relates to the methods forpreparing skin care preparations incorporating such combinations of herbextracts, as well as the methods for caring for the skin utilizing suchpreparations.

BACKGROUND

The use of various antioxidant compositions for counteracting thedeleterious effect of free radicals upon cells of the human body iswidely studied. Free radicals are implicated in a wide variety ofdiseases of the human body. Referring particularly to diseases of theskin, the presence of free radicals on the skin results from a number ofconditions, including over-production of free radicals within the cellitself, or exposure to external forces such as ultraviolet rays, coupledwith an inability of the cell itself to defend against theover-production. The resulting excess of free radicals is known to bethe cause of various skin disabilities, such as wrinkling, lack ofelasticity, and generalized aging, and there is a need to fortify andsupplement the various antioxidant mechanisms in the body.

Many compositions have been proposed and used in the past for providingthe desired antioxidant effect, including Vitamin E (tocopherol),Vitamin A (beta-carotene), Vitamin C (ascorbic acid), Trolox (a VitaminE analog), and the like. In addition, certain plant extracts have beenreported as having antioxidant properties, including extracts from birchBetula platyphylla) (JP-A-10-046143) and various plant extracts obtainedby extraction, with water or a lower alcohol or an aqueous lower alcoholsolution, of plants such as hibiscus, aloe, rhubarb, osei (polygonatirhizoma), bearberry leaf, enmeiso (plectranthi herba), yobaihi (nyricaecirtex), pueraria root, cnidium rhizome, atractylodes lancea rhizome,mentha leaf, glycyrrhiza, peony root, coix seed, sin'i (magnoliae flos),cinnamon bark, houttuynia herb, coptis rhizome, moutan bark, gentian,nutgall, swertia herb, geranium herb, phellodendron bark, dried ginger,scutellaria root, chulling (poly porus), garlic, sage, oregano,rosemary, laurel, celery, thyme, tarragon, nutmeg, mace, clove, Japanesehorseradish, savory, basil, red pepper, roasted bean, black tea, greentea, persimmon leaf, coffee, horsetail, henon bamboo, mugwort,Cynostemma species, low striped bamboo, matrimony vine, Cyrtomiumspecies, and shiitake mushrooms (JP-A6-024937).

[See US published patent application Publication No. 2004/0028643].

Personal care products such as body washes, lotions, liquid hand soaps,sunscreens, shampoos, and the like ordinarily contain a variety ofadditives designed to provide performance enhancing benefits such asmoisturizing, fragrance, colorant, anti-inflammatory, and anti-irritantproperties, and thus these personal care products provide a convenientvehicle for also applying antioxidants directly to the skin. Botanicalextracts are a source for many of the above performance enhancingproperties and accordingly are conventionally found as additives to thepersonal care products. To keep the number of additives withinreasonable bounds with respect to any particular skin care product, itwould be desirable to use herb extracts that provide not only one ormore of the performance enhancing properties but also an antioxidantproperty, and, more particularly, it would be beneficial to findcombinations of herb extracts that provide synergistic antioxidanteffects. That is, it would be useful to provide formulations ofdifferent herb extracts that would function synergistically to increasethe total antioxidant activity of the combined extracts in excess oftheir individual contributions.

SUMMARY OF THE INVENTION

In accordance with one embodiment, the present invention comprisesmixtures of herb extracts which exert synergistic antioxidant effect andcomprise the herb sophora and at least one other herb selected from thegroup consisting of honeysuckle, kudzu, and licorice.

In accordance with another embodiment, the invention comprises a skincare preparation comprising a base which is medicinally acceptable fordermal application and which contains an antioxidant effective mixtureof the herb sophora and at least one other herb selected from the groupconsisting of honeysuckle, kudzu, and licorice. The invention alsocomprises a method for the preparations of such skin preparation.

In accordance with another embodiment, the invention comprises a methodfor caring for the skin comprising applying to the skin a compositioncomprising an admixture of a base and an antioxidant effective mixtureof the herb sophora and at least one other herb selected from the groupconsisting of honeysuckle, kudzu, and licorice.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an XY scatter chart depicting the synergistic andnon-synergistic results from the use of various concentration ratios ofsophora/honeysuckle extract mixtures.

FIG. 2 is an XY scatter chart depicting the synergistic andnon-synergistic results from the use of various concentration ratios ofsophora/kudzu extract mixtures.

FIG. 3 is an XY scatter chart depicting the synergistic andnon-synergistic results from the use of various concentration ratios ofsophora/licorice extract mixtures.

DETAILED DESCRIPTION OF THE INVENTION

This detailed description of various exemplary embodiments of theinvention makes reference to exemplary compositions and methods. Whilethese embodiments are described in sufficient detail to enable thoseskilled in the art to practice the invention, it should be understoodthat other embodiments may also be realized, and that logical andprocessing changes may be made without departing from the spirit andscope of the invention. Thus, the detailed description herein is presentfor the purposes of illustration only and not of limitation.

In the development of the present invention, it was discovered thatcertain mixtures of extracts of the herb sophora with extracts of otherherbs such as honeysuckle, kudzu, and licorice provide a synergisticantioxidant effect when prepared within certain ranges of concentrationratios. The detailed description of this discovery with respect to eachherb mixture (i.e., sophora/honeysuclde, sophora/kudzu, andsophora/licorice) will be taken up separately in the sections to follow:

Mixtures of Sophora and Honeysuckle

Sophora flower is the dried flower of the Japanese pagoda tree (Sophorajaponica), which is native to Japan, China, Korea and other Eastern Asiacountries It is described as having numerous medicinal uses,particularly in traditional Chinese medicine, including use as ananti-inflammatory agent. The sophora flower extracts used in the presentstudy were obtained from Symrise GMBH & Co., KG., Holzminden, Germany,under the name Actipone® Sophora Flower. In the present specificationand claims, the extract will be referred to either as “sophora” or as“sophora flower.”

Honeysuckle is an herb extract obtained from the dried flowers of theplant Lonicera japonica. It is mentioned throughout history not only asa candy and food ingredient but also as a natural remedy for a widerange of ailments, including use for anti-inflammatory, anti-irritant,and vasodilatory effect. The honeysuckle extracts used in the presentstudy were obtained on the market from Symrise GMBH & Co., KG.,Holzminden, Germany, under the name Actipone® Honeysuckle Flower. In thepresent specification and claims, the extract will be referred to eitheras “honeysuckle” or “honeysuckle flower.”

In the development of the present invention, the measurement ofantioxidant activity was made using the oxygen radical absorbancecapacity (ORAC) assay described in the publication by Huang, D.; Ou, B.;Hampshe-Woodill, M.; Flanagan, J. A.; and Prior, R. I., entitled“High-throughput assay of oxygen radical absorbance capacity (ORAC)using a multichannel liquid handling system coupled with a microplatefluorescence reader in 96-well format”, 2002 J. Agric. Food Chem., 50,4437-4444. In these measurements, for each herb extract, thefluorescence decay curves of sodium fluorescein (Na₂Fl) induced by 2,2prime-Azobis(-amidopropane) dihydrochloride (AAPH) in the presence ofTrolox standards was evaluated. The ORAC measurement was performed at30° C. on a Synergy™ HT multi-detection microplate reader (Bio-TekInstruments, Inc., Winooski, Vt.) with an excitation wavelength of485±20 nm and emission wavelength of 530±20 nm. The plate reader wascontrolled by software KC4 3.4.

In these measurements, an 8.0×10⁻⁵ mM fresh Na₂Fl solution was madedaily by diluting the stock solution in 75 mM phosphate buffer (pH 7.4).AAPH (0.414 g) was completely dissolved in 10 ml of 75 mM phosphatebuffer (pH 7.4) to a final concentration of 150 mM and was kept in anice bath. Trolox standard was prepared as follows: 0.0125 g of Troloxwas dissolved in 10 ml MeOH solution to give a 0.5M stock solution. Thestock solution was diluted with the same phosphate buffer to 50, 25,12.5 and 6.25 μM, i.e. 12.5, 6.25, 3.13, and 1.56 μg/ml workingsolutions. These samples were used in each test as control. In eachtest, samples were freshly prepared by dissolving into 75 mM phosphatebuffer (pH 7.4) to make stock solution and then diluting and thephosphate buffer solution was tested as blank.

In the course of the work leading to the present invention, mixtures ofsophora and honeysuckle in a number of varying concentration ratios weretested for antioxidant effectiveness using the ORAC assay method. Thefluorescence decay curves of Na₂Fl induced by AAPH in the presence ofTrolox standards for each herb extract and the combination of herbextracts were plotted after each test. Their area under the curve(A.U.C.) was calculated. The net A.U.C. was calculated asA.U.C._(sample)−A.U.C._(blank). The net A.U.C. from the combination ofherb extracts and the sum of net A.U.C. from each herb extract werelisted in table and also plotted in diagram. The results of such testingfor a first group of mixtures, using sophora and honeysuckle are setforth in the following Table 1-A:

TABLE 1-A Sophora and Honeysuckle Sophora HoneyS (Net − Sum)/ Conc.Conc. Net Sum of Net − Sum * 100* μg/ml μg/ml A.U.C A.U.C. each herb Sum% 6.69 0 12.42 6.61 8.92 0 14.65 8.84 0 6.98 12.94 7.13 0 13.95 17.1511.34 6.69 6.98 19.34 13.53 13.74 −0.21 −1.53 8.92 6.98 21.24 15.4315.97 −0.54 −3.38 6.69 13.95 24.83 19.02 17.95 1.07 5.96 8.92 13.9525.31 19.5 20.18 −0.68 −3.37 Blank 5.81

It will be noted that, in the above Table 1-A, a positive percentagenumber in the (Net-Sum)/Sum*100 column indicates that the mixturespossesses synergistic effect, while a negative percentage numberindicates non-synergistic effect.

A second group of sophora/honeysuckle mixtures, but with concentrationratios differing from the first, was submitted to the same ORAC testing,with the results being shown in the following Table 1-B:

TABLE 1-B Sophora and Honeysuckle Sophora HoneyS (Net − Sum)/ Conc.Conc. Net Sum of Net − Sum * 100* μg/ml μg/ml A.U.C A.U.C. each herb Sum% 1.67 0 6.3 1.28 3.34 0 7.71 2.69 6.69 0 10.87 5.85 0 6.98 11.47 6.45 013.95 16.63 11.61 0 27.91 26.33 21.31 3.34 6.98 14.89 9.87 9.14 0.737.99 1.67 6.98 13.05 8.03 7.73 0.3 3.88 6.69 13.95 23.7 18.68 17.46 1.226.99 3.34 13.95 19.72 14.7 14.3 0.4 2.80 1.67 13.95 18.58 13.56 12.890.67 5.20 3.34 27.91 30.01 24.99 24 0.99 4.13 1.67 27.91 27.74 22.7222.59 0.13 0.58 Blank 5.02

It will be noted that, in the above Table 1-B, all numbers in the(Net-Sum)/Sum*100 column are positive numbers, indicating that allconcentration ratios provided synergism.

To summarize the synergistic and non-synergistic findings in the abovestudies, the synergistic ratios are tabulated below in Table 1-C, andthe non-synergistic ratios are set out below in Table 1-D:

TABLE 1-C Synergistic Sophora/Honeysuckle Concentration ratios SophoraHoneysuckle μg/ml μg/ml 6.69 13.95 3.34  6.98 1.67  6.98 3.34 13.95 1.6713.95 3.34 27.91 1.67 27.91

TABLE 1-D Non-synergistic Sophora/Honeysuckle Concentration ratiosSophora Honeysuckle μg/ml μg/ml 6.69 6.98 8.92 6.98 8.92 13.95 

The data of Tables 1-C and 1-D have been incorporated in an XY scatterchart which is presented in this application as FIG. 1. It will be notedthat the concentration ratios found to be synergistic are located withinthe area marked A on the chart.

To summarize all of the foregoing, in the embodiment of the inventioninvolving mixtures of sophora and honeysuckle, the concentration ratioswhich have been found to be synergistic are within the range of 1.0μg/ml≦C_(Sophora)≦8.0 μg/ml, 6.0 μg/ml≦C_(Honeysuckle)≦28.0 μg/ml.

Mixtures of Sophora and Kudzu

In the embodiment involving mixtures of sophora and kudzu, the sophorais the herb extract obtained from the Japanese pagoda tree (Sophorajaponica), which is described in more detail in the previous section.Kudzu is an herb extract obtained from the plant Pueraria lobata, whichis native to China and Japan but has been transplanted in many othercountries of the world, including the United States. It is described ashaving numerous medicinal uses, particularly in traditional Chinesemedicine. The kudzu extracts used in the present study were on themarket from Symrise GMBH & Co., KG., Holzminden, Germany, ActiponePueraria Root. In the present specification and claims, the extract willbe referred to as “kudzu”.

In the development of the sophora/kudzu embodiment of the presentinvention, the measurement of antioxidant activity was made using theoxygen radical absorbance capacity (ORAC) assay, which is described indetail in the preceding section relating to the sophora/honeysuckleembodiment.

In the course of the work leading to the present invention, mixtures ofsophora and kudzu in a number of varying concentration ratios weretested for antioxidant effectiveness using the ORAC assay method toobtain net A.U.C. values, and the results of such testing for a firstgroup of mixtures are set forth in the following Table 2-A:

TABLE 2-A Sophora and Kudzu Sophora Kudzu (Net − Sum)/ Conc. Conc. NetSum of Net − Sum * 100* μg/ml μg/ml A.U.C A.U.C. each herb Sum % 1.67 06.3 1.28 3.34 0 7.71 2.69 6.69 0 10.86 5.84 0 3.56 14.22 9.2 0 7.1222.74 17.72 0 14.24 35.62 30.6 6.69 3.56 21.68 16.66 15.04 1.62 10.773.34 3.56 18.34 13.32 11.89 1.43 12.03 1.67 3.56 17.07 12.05 10.48 1.5714.98 6.69 7.12 29.99 24.97 23.56 1.41 5.98 1.67 7.12 25.88 20.86 191.86 9.79 6.69 14.24 44.52 39.5 36.44 3.06 8.40 3.34 14.24 42.23 37.2133.29 3.92 11.78 1.67 14.24 39.88 34.86 31.88 2.98 9.35 Blank 5.02

It will be noted that, in the above Table 2-A, all numbers in the(Net-Sum)/Sum*100 column are positive numbers, indicating that allconcentration ratios provided synergism

A second group of sophora/kudzu mixtures, but with concentration ratiosdiffering from the first, was submitted to the same ORAC testing, withthe results being shown in the following Table 2-B:

TABLE 2-B Sophora and Kudzu Sophora Kudzu (Net − Sum)/ Conc. Conc. NotSum of Net − Sum * 100* μg/ml μg/ml A.U.C A.U.C. each herb Sum % 0.84 05.94 0.74 6.69 0 11.58 6.38 13.38 0 17.94 12.74 26.75 0 31.95 26.75 01.78 10.21 5.01 0 14.24 36.56 31.36 0 28.48 70.22 65.02 0.84 1.78 12.066.86 5.75 1.11 19.30 6.69 1.78 17.51 12.31 11.39 0.92 8.08 13.38 1.7824.67 19.47 17.75 1.72 9.69 26.75 1.78 35.68 30.48 31.76 −1.28 −4.030.84 14.24 41.86 36.66 32.1 4.56 14.21 6.69 14.24 44.95 39.75 37.74 2.015.33 26.75 14.24 60.78 55.58 58.11 −2.53 −4.35 0.84 28.48 69.59 64.3965.76 −1.37 −2.08 6.69 28.48 72.54 67.34 71.4 −4.06 −5.69 13.38 28.4873.25 68.05 77.76 −9.71 −12.49 Blank 5.2

It will be noted that, in the above Table 2-B, a positive percentagenumber in the (Net-Sum)/Sum*100 column indicates that the mixturespossesses synergistic effect, while a negative percentage numberindicates non-synergistic effect.

A third group of sophora/kudzu mixtures, but with concentration ratiosdiffering from the first two, was submitted to the same ORAC testing,with the results being shown in the following Table 2-C:

TABLE 2-C Sophora and Kudzu Sophora Kudzu (Net − Sum)/ Conc. Conc. NetSum of Net − Sum * 100 μg/ml μg/ml A.U.C A.U.C. each herb Sum % 6.69 011.21 5.72 11.15 0 15.15 9.66 22.29 0 24.49 19 0 0.89 7.61 2.12 0 7.1224.41 18.92 0 11.86 34.45 28.96 0 23.73 58.99 53.5 22.29 11.86 61.5356.04 47.96 8.08 16.85 22.29 7.12 50.18 44.69 37.92 6.77 17.85 22.290.89 31.72 26.23 21.12 5.11 24.20 11.15 23.73 71.22 65.73 63.16 2.574.07 11.15 11.86 49.84 44.35 38.62 5.73 14.84 11.15 7.12 35.56 30.0728.58 1.49 5.21 11.15 0.89 18.85 13.36 11.78 1.58 13.41 6.69 23.73 65.9960.5 59.22 1.28 2.16 6.69 11.86 42.01 36.52 34.68 1.84 5.31 6.69 7.12 3125.51 24.64 0.87 3.53 6.69 0.89 13.68 8.19 7.84 0.35 4.46 Blank 5.49

It will be noted that, in the above Table 2-C, all numbers in the(Net-Sum)/Sum*100 column are positive numbers, indicating that allconcentration ratios provided synergism

To summarize the synergistic and non-synergistic findings in the abovetwo studies relating to mixtures of sophora and kudzu, the synergisticratios are tabulated below in Table 2-D, and the non-synergistic ratiosare set out below in Table 2-E:

TABLE 2-D Synergistic Sophora/Kudzu Concentration ratios Sophora Kudzuμg/ml μg/ml 6.69 3.56 3.34 3.56 1.67 3.56 6.69 7.12 1.67 7.12 6.69 14.243.34 14.24 1.67 14.24 0.84 1.78 6.69 1.78 13.38 1.78 0.84 14.24 6.6914.24 22.29 11.86 22.29 7.12 22.29 0.89 11.15 23.73 11.15 11.86 11.157.12 11.15 0.89 6.69 23.73 6.69 11.86 6.69 7.12 6.69 0.89

TABLE 2-E Non-synergistic Sophora/Kudzu Concentration ratios SophoraKudzu μg/ml μg/ml 26.75 1.78 26.75 14.24 0.84 24.48 6.69 28.48 13.3828.48

The data of Tables 2-D and 2-E have been incorporated in an XY scatterchart which is presented in this application as FIG. 2, relating tomixtures of sophora and kudzu extracts. It will be noted that theconcentration ratios found to be synergistic are located within the areamarked A on the chart.

To summarize the above data for the embodiment of the inventioninvolving mixtures of sophora and kudzu extracts, the concentrationratios which have been found to be synergistic are within the range of0.5 μg/ml≦C_(Sophora)≦25.0 μg/ml, 0.5 μg/ml≦C_(Kudzu)≦25.0 μg/ml.

Mixtures of Sophora Flower and Licorice

In the embodiment involving mixtures of sophora flower and licorice, thesophora flower is the herb extract obtained from the Japanese pagodatree (Sophora japonica), which is described in more detail in a previoussection. Licorice is an herb extract obtained from the root of theGlycyrrhiza glabra plant, which is indigenous to many subtropicalclimes, including China, Greece, Spain, Turkey, and Iraq. It ismentioned throughout history not only as a candy and food ingredient butalso as a natural remedy for a wide range of ailments, including use foranti-inflammatory effect. The licorice extracts used in the presentstudy were obtained on the market from Symrise GMBH & Co., KG.,Holzminden, Germany, under the name Actipone® Licorice Root. In thepresent specification and claims, the extract will be referred to as“licorice”.

In the course of the work leading to the present invention, mixtures oflicorice and sophora in a number of varying concentration ratios weretested for antioxidant effectiveness using the ORAC assay method toobtain net A.U.C. values, and the results of such testing for a firstgroup of mixtures, using licorice (liquid) and sophora (liquid) obtainedfrom Symrise are set forth in the following Table 3-A:

TABLE 3-A Licorice (Liquid) and Sophora (Liquid) Sophora Licorice (Net −Sum)/ Conc. Conc. Net Sum of Net − Sum * 100* μg/ml μg/ml A.U.C A.U.C.each herb Sum % 6.69 6.92 18.1 12.29 10.53 1.76 16.71 8.92 6.92 21.4115.6 12.79 2.81 21.97 13.38 6.92 25.69 19.88 17.16 2.72 15.85 6.69 13.8422.77 16.96 14.35 2.61 18.19 8.92 13.84 24.5 18.69 16.61 2.08 12.5213.38 13.84 29.29 23.48 20.98 2.5 11.92 6.69 0 12.42 6.61 8.92 0 14.688.87 13.38 0 19.05 13.24 0 6.92 9.73 3.92 0 13.84 13.55 7.74 Blank 5.81

It will be noted that, in the above Table 3-A, all numbers in the(Net-Sum)/Sum*100 column are positive numbers, indicating that allconcentration ratios provided synergism.

A second group of licorice/sophora mixtures, but with concentrationratios differing from the first, was submitted to the same ORAC testing,with the results being shown in the following Table 3-B:

TABLE 3-B Licorice (Liquid) and Sophora (Liquid) Sophora Licorice (Net −Sum)/ Conc. Conc. Net Sum of Net − Sum * 100* μg/ml μg/ml A.U.C A.U.C.each herb Sum % 1.67 0 7.78 2.08 3.34 0 8.46 2.76 6.69 0 10.58 4.8813.38 0 17.65 11.95 26.75 0 29.6 23.9 0 1.73 6.62 0.92 0 3.46 7.42 1.720 6.92 9.59 3.89 0 13.84 13.43 7.73 0 27.68 20.86 15.16 1.67 27.68 25.5719.87 17.24 2.63 15.26 1.67 6.92 12 6.3 5.97 0.33 5.53 1.67 1.73 8.482.78 3 −0.22 −7.33 3.34 27.68 26.95 21.25 17.92 3.33 18.58 3.34 6.9213.46 7.76 6.65 1.11 16.69 3.34 3.46 11.18 5.48 4.48 1 22.32 6.69 13.8420.85 15.15 12.61 2.54 20.14 6.69 3.46 14.44 8.74 6.6 2.14 32.42 6.691.73 13.22 7.52 5.8 1.72 29.66 13.38 27.68 35.62 29.92 27.11 2.81 10.3713.38 6.92 21.65 15.95 15.84 0.11 0.69 26.75 13.84 45.33 39.63 31.63 825.29 26.75 1.73 30.62 24.92 24.82 0.1 0.40 Blank 5.7

It will be noted that, in the above Table 3-B, a positive percentagenumber in the (Net-Sum)/Sum*100 column indicates that the mixturespossesses synergistic effect, while a negative percentage numberindicates non-synergistic effect.

A third group of licorice/sophora mixtures, but with concentrationratios differing from the first two, was submitted to the same ORACtesting, with the results being shown in the following Table 3-C:

TABLE 3-C Licorice (Liquid) and Sophora (Liquid) Sophora Licorice (Net −Sum)/ Conc. Conc. Net Sum of Net − Sum * 100* μg/ml μg/ml A.U.C A.U.C.each herb Sum % 0 27.68 24.43 18.92 0 39.54 32.97 27.46 0 55.35 45.5740.06 1.67 0 6.64 1.13 6.69 0 11.21 5.7 26.75 0 29.03 23.52 1.67 27.6825.16 19.65 20.05 −0.4 −2.00 1.67 39.54 33.2 27.69 28.59 −0.9 −3.15 1.6755.35 46.56 41.05 41.19 −0.14 −0.34 6.69 39.54 38.05 32.54 33.16 −0.62−1.87 6.69 55.35 50.3 44.79 45.76 −0.97 −2.12 26.75 27.68 48.65 43.1442.44 0.7 1.65 Black 5.51

It will be noted that, in the above Table 3-C, a positive percentagenumber in the (Net-Sum)/Sum*100 column indicates that the mixturespossesses synergistic effect, while a negative percentage numberindicates non-synergistic effect.

To summarize the synergistic and non-synergistic findings in the abovethree studies, the synergistic ratios are tabulated below in Table 3-D,and the non-synergistic ratios are set out below in Table 3-E:

TABLE 3-D Synergistic Licorice/Sophora Concentration ratios SophoraLicorice μg/ml μg/ml 6.69 6.92 8.92 6.92 13.38 6.92 6.69 13.84 8.9213.84 13.38 13.84 1.67 27.68 1.67 6.92 3.34 27.68 3.34 6.92 3.34 3.466.69 3.46 6.69 1.73 13.38 27.68 26.75 13.84 26.75 1.73 26.75 27.68

TABLE 3-E Non-synergistic Licorice/Sophora Concentration ratios SophoraLicorice μg/ml μg/ml 1.67  1.73 1.67 27.68 1.67 39.54 1.67 55.35 6.6939.54 6.69 55.35

The data of Tables 3-D and 3-E have been incorporated in an XY scatterchart which is presented in this application as FIG. 3. It will be notedthat the concentration ratios found to be synergistic are located withinthe area marked A on the chart.

To summarize all of the foregoing, in the embodiment of the inventioninvolving mixtures of licorice and sophora, the concentration ratioswhich have been found to be synergistic are within the range of 1.5m/ml≦C_(Sophora)≦27.0 μg/ml, 1.5 μg/ml≦C_(Licorice)≦28.0 μg/ml.

In the practice of the invention, the plant extract combinationsmentioned above may be included in any suitable skin care basesmedicinally acceptable for dermal application, including various baseformulations such as liquids, creams, gels, foams, lotions, body washes,liquid hand soaps, shampoos, antiperspirants, deodorants, and the like.Such base formulations conventionally contain known skin careingredients, such as found in “CFTA Cosmetic Ingredient Handbook,” J. M.Nikitakis, ed., The Cosmetic, Toiletry and Fragrance Association, Inc.,Washington, D.C. (1988), incorporated herein by reference. Suchingredients include, but not by way of limitation, numerous enhancingelements, such as alcohols, oleaginous substances, surfactants,preservatives, emollients, perfumes, colorants, humectants, thickeningagents, skin care agents, water-soluble polymers, chelating agents, pHadjusting agents, foaming agents, antimicrobial agents, vitamins, andthe like.

Examples of the above-mentioned surfactants include, but are not limitedto, lauryl sulfates, octyl sulfates, 2-ethylhexyl sulfates, lauramineoxides, decyl sulfates, tridecyl sulfates, cocoates, laurylsulfosuccinates, lauryl sarcosinates, lauryl ether sulfates (1 and 2moles ethylene oxide), myristamine oxide, ricinoleates, cetyl sulfates,alkyl glucosides, and similar surfactants.

Examples of the above preservatives include benzoic acid salts,salicylic acid salts, sorbic acid salts, dehydroacetic acid salts,parahydroxybenzoic acid esters, benzalkonium chloride,2,4,4′-trichloro-2′-hydroxydiphenyl ether, 3,4,4′-trichlorocarbanilide,hinokitiol, resorcinol, and ethanol.

Examples of humectants include glycerin, sodium pyrrolidone carboxylate,and the like. Examples of foam stabilizers include cetyl alcohol,cetearyl alcohol, stearic acid, and the like. Examples of skin careagents include guar gum, hydroxyethylcellulose,hydroxypropylmethylcellulose, polyethylene glycol, hydrolyzed wheatprotein, polyoxyethylene stearyl ether, and the like.

The actual formulation of the skin care consumer products incorporatingthe plant extract combinations of the present invention is throughstandard methods of manufacturing. All the liquid formulations areeasily made in batch mixtures, with addition of water usually first,such that the liquid is above the mixing impeller within the tank. Thenthe specialty chemicals, such as the surfactants are added, followed bythe dyes, preservatives, plant extract combinations, etc. The methods ofmanufacture are well known.

While numerous exemplary embodiments of the invention have beenpresented in the foregoing detailed description of the invention, itshould be appreciated that a vast number of variations exist. It shouldalso be appreciated that the exemplary embodiments are only examples,and are not intended to limit the scope, applicability, or configurationof the invention in any way. Rather, the foregoing detailed descriptionwill provide those skilled in the art with a convenient road map forimplementing an exemplary embodiment of the invention, it beingunderstood that various changes may be made in the function andarrangement of elements described in an exemplary embodiment withoutdeparting from the scope of the invention set forth in the appendedclaims and their legal equivalents.

We claim:
 1. A composition of herb extracts having antioxidantproperties, comprising a mixture which exerts synergistic antioxidanteffect and comprises the herbs sophora and kudzu within theconcentration range of 0.5 μg/ml≦C_(Sophora)≦25.0 μg/ml, 0.5μg/ml≦C_(kudzu)≦25.0 μg/ml.
 2. A composition of herb extracts whichprovides synergistic antioxidant effects, comprising a mixture ofsophora and kudzu extracts having a concentration ratio fallingapproximately within the area marked A in the chart shown in FIG. 2hereof.
 3. A skin care preparation comprising a base medicinallyacceptable for dermal application and having mixed therein thecomposition of herb extracts as defined in claim
 1. 4. A skin carepreparation comprising a base medicinally acceptable for dermalapplication and having mixed therein the composition of herb extracts asdefined in claim
 2. 5. A method for making a skin care preparation, themethod comprising admixing a base and the synergistic antioxidantcomposition as defined in claim
 1. 6. A method for making a skin carepreparation, the method comprising admixing a base and the synergisticantioxidant composition as defined in claim
 2. 7. A method for caringfor the skin comprising applying to the skin a skin care preparation asdefined in claim
 3. 8. A method for caring for the skin comprisingapplying to the skin a skin care preparation as defined in claim 4.